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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - bolts - confused!

Hi, first time caller here! I'm sure this has been asked and covered before but here goes. We are working on a 52 TD and trying to understand these bolts & threads. The 5/16 dia are 25 22 20 TPI for the most part and the 25 is 8mm x 1.0p. As a last resort, I can use hardware store stuff, but I would rather use originals, where can I get them? ASL sells 5/16-26, what are these? Also, there are 8-10 different mfg's, Sparts Woten C S C Rubbery-Owens & plain (no stamp) etc etc etc. why so many? Is there someplace on-line that has this info and can someone send me a link? Many THX. Frank
F Grand

Frank - Go to my web site at: Click on Other Tech Articles, then on the Fasteners and Wrenches Articles for T series MGs and see the charts there. When you are finished, e-mail me and I will send you several other articles that explain the the idiosyncrasies of the fastener system use on our cars. Cheers - Dave
David DuBois

Frank - Moss Motors also sells hardware for the cars - they have a specific page in the catalog with various bolts and nuts.

Also - are you a member of the Atlanta-based Southeastern MGT Register? Our club is very active and we are happy to help you out.

Hope to hear from you,

J. W. Delk

First, welcome to the best place for these questions and to this brotherhood of M.G. owners. You will find this group an indespicable wealth of knowledge as well as just plain friendly folks waiting to help! (I know I have over the last 8 or so years I have been visiting here)
David D. has you pointed in the right direction with his excellent info on his site for FASTENERS AND WRENCHES ARTICLES.

One word of caution ...DO NOT fall into the trap of "hardware store stuff". Although this can be fine for "some items" my car was a mess when I first got it because my PO had cross threaded many of my fasteners with off the shelf bolts that were "close" to the right thread. Re-tapping and fixing these was a long & painful process. (engine block!)

I'm not sure if they still offer it but Abingdon Spares had a "hardware assortment" they sold for these cars I had purchased years ago that has proved invaluable to me as recently as last week! During my rebuild I ordered hardware from several places but that "spares" kit has saved me many times and an assortment of it "lives" in my boot so as to always be with the car for long trips. (most "Napa" sales clerks look at you like a deer in the headlamps when you mention "Whitworth"!)Strangly enough I took a pic of my "spares kit" yesterday..don't know why...but I did.
Cheers & best of luck...we will look forward to your post in the coming weeks, months, years!
David 55 TF1500 #7427

David Sheward

Frank, Also get a copy of the NEMGTR's "T-series Handbook nut and bolt article. Abindgon Spares also has a just nut and bolt assortment for $85 (item 66/67)which if doing major restoration or rebuild is more than worth it- I much of it up doing my restoration. It contains most of the common body/chassis sized items. Abingdon also has specialty nuts such as the square captive nuts used in the tub. All of the engine/tranny stuff is fine-thread French metric, lots of 8mm x 1.0, etc. A tap that size is indespensible if you are doing the motor or tranny. The various bolt head markings are just of the manufacturer at the time. I understand they varied from car to car. In the recently released "Inside the Octagon Vol. 2" (or whatever it is called), there is an interview with long-time MG mangaging director John Thornley. John says he is always asked questions at MG events about bolts, and his answer was basically use whatever, because when the factory ran out, they sent someone to the hardware store to buy what they needed! George
George Butz

Dave, if it came with the electrical tape and the JB Weld I'm gonna have to buy a set.

I'll throw my two cents in here... having worked on cars where 'any bolt will do' and cars with BSF bolts and Mad Metric Bolts with Whitworth flats, I can assure you that the latter is much perferable! You can grab the right wrench, the correct tab, and use the right tools for the right job. I was so dismayed that my 'Whitworth Shop' floor boards had SAE T-Nuts in them that I rummaged in my garden until I found the remains of my original floor boards, scavanged the T-Nuts followed my cleaning proceedure and substituted them into my floorboards. Why? Because two years from now when I'm taking out my seats, I'll be thrilled to have the right wrench in my hands out of habbit.

There are a few places where substitution of nuts was unavoidable, the windshield received longer, stainless steel SAE hardware to go through the inexplicitly longer wood. There are several places on the engine where I succumbed and installed metric fastners, mostly at the gearbox to bell housing mate because finding Mad Metric fastners seemed maddening. AND you can readily identify a metric head from a whitworth head.

I did buy where needed new fastners from Moss, or scavagened them from other projects. I made my own square captive nuts in the 5/16 and 1/4 inch sizes as needed.

My process for reclaiming the bolts and nuts was 1) completely bagging the dirty fastners on disassembly and photographing them with their labels to scale. 2) Tumbling in the Eastwood green pryamids with a cup of water for 36 hours and 3) in the dry shine media for 8 hours. 4) Chasing every thread with a tap or die and then 5) silver cad plate or paint depending on the application and 6) finally rebagging them with their labels for future installation. Mainly cad for below the chassis, paint other places. There are a few spots where I didn't follow this procedure and I'm discovering that some rust cleaning and paint is in my near future.

Hope this helps,
Dave Braun

I'm pretty sure "item 66/67" from Abingdon Spares that George mentioned is the same "kit" I purchased years ago (somewhat cheaper then!) The kit was considerably larger than what I carry "in car" for spares. Well worth the money to have them on hand when needed. I am very lucky in that I live near a store that sells nothing but fasteners (Phoenix Rose Company Fasteners, Newark Ohio) and we have been able to order and/or find good replacement for nearly everything on the car.
I had quite a "Hodge-podge" of fastnerers of the TF when I bought it. The "purest" will come after me for this, but when I reassembled my car I used much stainless-steel metric. All the old "correct" cadmium bolts were media blasted clean and stored with bags of rice to keep from rusting again so the next guy can put them back on when and if they desire.
The electrical tape, JB Weld, bailing wire ect did not come with the "kit" but it could come in handy! I enlarged my "boot box" and added a lock to it so I carry a lot of spares. (Murphy's law: If you carry it you will never need it...leave it in the garage and you'll need it!)
David 55 TF1500 #7427
David Sheward

David, So true about leaving stuff in the garage! A few years ago, I was driving up to Sturbridge, Ma. for a GOF, when my engine started to miss terribly and loose power. I got off of the highway in the middle of rural Connecticut when the car would go no further. The first thing that I did was remove the distributer cap to check the points and it became evident that the drive seal had leaked and the inside of the cap was covered with oil. I cleaned it thoroughly and put it together, but it would not run smoothly. I figured that one or more plugs had fouled. When I got out my wrenches and complete ratchet set, I found that the only socket that I own that wasn't with me on this trip was the correct 13/16 plug wrench. Of course, I had a fresh set of plugs...water water everywhere, but not a drop to drink! Fortunately for me, the next mile or so of roadway was downhill, so we coasted and, very luckily, we came upon an auto repair shop-the only business for miles in either direction. I had to swallow my pride and borrow a socket, and within a few minutes, we were on our way.
Steven Tobias

F Grand

The above have not really answered you in your understanding.

The T series body has only British Standard Fine threads (BSF) in thw Whitworth pattern (56 degree rounded thread, Not 60 degree pointed thread as in US and ISO Metric threads) The bolt heads are Whitworth sizes and are catagorized by the diameter of the bolt, , not the head)

Thus a 1/4 inch BSF bolt is a 1/4 inch in diameter with 26 threads per inch and has a head that is a little larger than 7/16 inch, whereas a US 1/4 in fine thread bolt has 28 TPI and a 7/16 US wrench fit s the head.
The corresponding BSF wrench is marked 1/4 BSF, the Whitworth wrench that fits is marked 3/16 W ( Historical problem).

Similarly, the 5/16 BSF bolt has a larger head and a thread that lies between US Fine and Coarse thread. The corresponding British Coarse thread (Whitworth) is the same as the US Coarse but with the different 56 degree profile. The wrench is marked 5/15 BSF or 1/4 W not 9/16.

The engine and tranmsission however are very different however as they have French Standard Metric (NOT ISO METRIC) bolts and nuts but with heads that Whitworth wrenches will fit (NOT METRIC OR US) These sizes are a mix of metric coarse and fine thread ( 6 x 1 mm, 8 x 1 mm, 10 x 1.5 mm, 12 x 1.5 mm, etc, but with Whitworth heads)

Late TD's and all TF's have Unified threads on th rear axle (same as US Fine)

Otherwise any changes from this is due to the Dreaded Previous Owner (DPO) A common problem, often leading to stripped nuts and bolts.
Don Harmer

Just in case you were wondering....the engine design was purchased from France and rather then retooling, they kept the metric, but so British mechanics could work on them with Witworth tools, they had manufactured metric threaded bolts with witworth heads on them.... (just in case it wasn't all confusing enough)...

We had a '57 MGA in '60 or so that must have gotten all the leftovers and many new.... what a job to work on!!!!

I defer to the experts but have just dismantled my front wings and needed to order for a missing wing-frame bolt. The existing one I measure at a 1/4 inch dia bolt and both my 1/4 Whitworth wrench and socket fit it not the 7/16.
The overall length (including bolt head)is just under 1 inch. I'm assuming that I'd need to order Moss #320-765, a 1/4 BSF 1 inch bolt.
R Biallas

To those on this BBS who are looking for bolts etc. I would suggest that you contact Doug Pelton at "". He has beem amassing a supply of nuts and bolts as well as many small items that are hard to locate for our "T's". Rod Murray and I were fortunate to meet Doug at his place in Phoenix this past winter, and although his inventory leans toward the TC series, many items are interchangable with the TD & TF series. He has brought back a TC parts car, and it looks like it has just come from the show room floor.

George Raham
TD 4224
G. L. Raham

Randy - "The existing one I measure at a 1/4 inch dia bolt and both my 1/4 Whitworth wrench and socket fit it not the 7/16."

Are you absolutely sure that the bolt is 1/4 BSF? It really should be a 5/16 BSF for that application. Is it possible that some DPO could have stuffed something into the female thread on the chassis to close up the hole to 1/4". Also, a 1/4 Whitworth wrench fits a 1/4 Whitworth bolt, and a 5/16 BSF bolt. This is where confusion set in. The head of a Whitworth bolt (course thread) was over sized for what was really needed and when they came up with the BSF bolts (fine thread), they went to the next size smaller head size. Thus, for a 5/16 BSF bolt, a 1/4 W wrench or a 5/16 BSF wrench is used. Until one gets used to the system, it gets real confusing real fast. Cheers - Dave
David DuBois

Thanks Dave
The existing bolt threads in easily so don't think it is wrong size/pitch. It could well be a 5/16 if the 1/4 W wrench can be used on a 5/16BSF. I don't have a gauge, just eyeballed it with a tape measure across the diameter. I'll go with you experts on it being a 5/16 BSF bolt for that part! Normally I just use whatever wrench/socket that fits among my collection of metric/whitworth/sae and not know the sizes! Fortunately haven't had to order many bolts/nuts. The bible catalogs from Moss/AB don't list any bolts for the wing/fenders so flying blind. No kidding this bolt/nut size stuff is confusing!
R Biallas

Randy - Go to the section of my web site listed in my first posting on this thread for information on the fasteners used in the engine, a comparison of wrench sizes and a rather comprehensive comparison of standard fasteners that Don Harmer did some years ago. I also have some other information that I haven't put on my web site that I can send you if you want. Just e-mail me at Cheers - Dave
David DuBois

All of the wing to frame/captive nut (rear fenders) and through and through (running boards to fender, etc) bolts are 5/16ths. The slotted head screws in the rear areas are 1/4 BSF. Of course most of the replacement BSF hardware has metric heads to further confuse the issue. George
George Butz

Hi Frank: Try They carry most of the bolts needed for our cars. They also have a good selection of british tools. Hope this helps.

Best wishes,

Stuart J. Ramos

See for a listing (from Abingdon Spares) of the TD Body Bolts and Nuts.
Bud Krueger

Thanks Bud!
Been to your site many times, didn't remember seeing that listing. Have added to my files. Good thing I was about to order a 1" and not the needed 3/4".
R Biallas

I second British Fasteners- a great resouce for not only the nuts/bolts, but taps and dies also. We are very lucky that Bud and the Daves have the huge amount of T-series information on the web and organized, etc. - I am always greatful for their time and efforts! George
George Butz

I recently tumbled to someone on ebay who sells stainless steel BSF, BA etc. fasteners at much less than Moss and Abingdon sell ordinary steel BSF bolts and nuts. (and less than my local hardware sells Stainless US bolts)
Unfortunately they are in the UK so shipping is more expensive than from US suppliers.

For example: 0.38 USD for a 5/16 SS BSF by i inch bolt vrs 1.30 USD from Moss for the same in ordinary steel .(in lots of 10) Corresponding SS BSF nuts (in lots of 20) and they have BA also (This is 2.30 GBP for 10 ea 5/16 X 1 BSF Set Screws which are threaded all he way)

Shipping charges add to these prices but can be optinimized by buying a moderate number of bolts and nuts at least one or so pounds weight.

They are Wye Valley Fasteners and their ebay store has prepackaged lots at low "BUY-IT-NOW" prices

the TF we are rebuilding (a rust bucket) we are using all Stainless Steel fasteners!!!!!

Don Harmer
Don Harmer

Addendum to Stainless above

the TF we are rebuilding (a rust bucket) we are using all Stainless Steel BSF and BA fasteners!!!!!

(except the chrome plated ones on windshield and the Mad-metric on the engine.tranny)
Don Harmer

This thread was discussed between 29/05/2009 and 02/06/2009

MG TD TF 1500 index

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